New Delhi, A study has related a cancer-associated gut microbiome pattern with a lower intake of dietary fibre and conversely, increasing intake of dietary fibre was related with a reduced signature of colorectal cancer in the microbiome.
Findings published in the journal Cell Host and Microbe suggest that diet, especially consuming fibre, can influence colorectal cancer risk, progression or prevention by shaping gut microbial communities.
Researchers, including those from the European Molecular Biology Laboratory, re-analysed data from 27 previously published studies, comprising 6,779 publicly available gut microbiome sequencing profiles.
They also analysed 906 intestinal tissue samples to compare stool-based microbiome signals with microbes found directly in tumour tissue.
The team identified a robust microbial signature associated with colorectal cancer.
“The strength of this study is its comprehensiveness,” author Georg Zeller, visiting team leader at European Molecular Biology Laboratory (EMBL) Heidelberg, Germany, and professor at the Leiden University Medical Center, the Netherlands, said.
“We combined stool and tissue comparisons, dietary data, taxonomic analysis down to bacterial strains, and functional analysis of virulence factors,” Zeller said.
In tissue samples, cancer-associated microbes could already be detected in early-stage tumours. In stool samples, however, the detection accuracy was somewhat lower in early-stage cancers and in tumours located further upstream in the colon.
The authors wrote, “This study, to our knowledge, represents one of the largest single-disease microbiome meta-analyses based on consistent re-profiling to date, encompassing a total of 6,779 faecal and 906 intestinal tissue samples from 34 study populations.”
They “documented a significant inverse relation between dietary fibre intake, for which strong epidemiological evidence supports a cancer-protective role, and the CRC (colorectal cancer) microbiome score, both in cancer patients and tumour-free individuals.”
“More importantly, we also showed that several interventions aimed at increasing dietary fibre content effectively lowered CRC microbiome scores,” the team said.
The approach enabled the researchers to establish a colorectal cancer microbiome signature that was not limited to one cohort, geography, sequencing method, or age of diagnosis.
Instead, the signature appeared to be a broadly reproducible feature of the disease, including both early-onset and late-onset colorectal cancer, they said.
Further, because the machine-learning algorithm used in the study can be applied to existing microbiome datasets, including dietary intervention studies, the approach may help scientists better understand how lifestyle factors influence disease-associated microbiome patterns in studies beyond those covered in the current analysis, the researchers said.
They also highlighted the power of open data and large-scale evidence synthesis in microbiome research.
By combining thousands of publicly available microbiome profiles, the researchers were able to identify robust patterns that would have been difficult to detect in individual studies alone, the team said.
